Considerable effort has been directed to the development of rechargeable batteries that have solid rather than liquid electrolytes. A solid electrolyte battery exhibits practical advantages, such as freedom from fluid leakage, but, can also exhibit low ionic conductivities. Solid electrolytes with higher ionic conductivities have been developed for the alkali metal ions, for example, sodium and lithium. However, these materials exhibit undesirable characteristics, such as very high reactivity with water. Batteries having lithium based solid electrolytes and a lithium electrode must be carefully sealed to prevent the occurrence of potentially hazardous reactions between the electrode and the moisture in the air.
Those skilled in the art will readily see the advantage of forming solid electrolyte energy sources with less reactive materials. Such an energy source would not have to be sealed and would be much more mechanically robust than prior art batteries.
Some of this effort has led to the development of electrochemical capacitor technologies engineered around proton conducting aqueous, acidic and alkaline electrolytes. In these systems, the optimum obtainable voltage is about 1.2 volts, i.e., the decomposition potential for water. Because of this limitation, research has turned to polymer based systems, such as the solid state polymer batteries and also in materials with different reversible potentials to obtain voltages higher than the aqueous systems.
It would be highly desirable and a significant contribution to the art if an energy storage device could be devised that would be free of the problems demonstrated by the alkali metal batteries and could also have a decomposition potential higher than that limited by the aqueous batteries.